Publications / 2014 Proceedings of the 31st ISARC, Sydney, Australia

Energy-Efficient Air-Cooled DX Air-Conditioning Systems with Liquid Pressure Amplification

V. Vakiloroaya, Q.P. Ha
Pages 489-498 (2014 Proceedings of the 31st ISARC, Sydney, Australia, ISBN 978-0-646-59711-9, ISSN 2413-5844)

The objective of this study is to explore an optimal strategy on energy consumption for a direct expansion (DX) air-conditioning system by using a refrigerant pump in the liquid line to allow the system to operate at a lower condensing pressure. An existing DX rooftop package of a commercial building located in a hot and dry climate zone is used for data collection. The theoretical-empirical modelling approach is used to obtain system model, from which the proposed strategy is formulated. A numerical algorithm is developed to analyse the system transient performance, using an iterative loop. As a minimum pressure differential is required across the expansion device, liquid pressure amplification (LPA) devices can be used on DX systems that operate with fixed head pressure control. They can be fitted to new or existing systems. Results show that the LPA approach is more effective when the ambient temperature is falling, with electricity saving around 25.3% in average.

Keywords: Energy Saving; Experimental Study; HVAC; Modelling; Liquid Pressure Amplification